Challenges in Diagnosing and Managing Severe Hypernatremia in Patients With Major Depressive Disorder: A Case Report

Hypernatremia, characterized by a plasma sodium concentration above 145 mmol/L, is frequently observed in critically ill patients, often due to factors such as gastrointestinal losses, dehydration, and diabetes insipidus. Psychiatric patients, particularly those with major depressive disorder, are also at risk of developing hypernatremia due to abnormalities in thirst sensation, mineralocorticoid excess, or medication side effects. Severe hypernatremia in psychiatric patients is associated with a high mortality rate, presenting challenges in diagnosis and management. The treatment of chronic hypernatremia (>48 hours) typically involves administering isotonic saline to hypovolemic patients until normalization of vital signs, followed by dextrose 5% in water (D5W) based on water deficit and losses. The goal is to decrease plasma sodium by 8-10 mmol/day. Acute hypernatremia (<48 hours) is corrected with a plasma sodium reduction of 1 mmol/L/hour in the first six to eight hours. While there are no clear guidelines for sodium correction in severe hypernatremia, the literature suggests a safe correction rate of 8-10 mmol/day for chronic hypernatremia and 1 mmol/L/hour for acute cases. In a specific case, a 51-year-old female with severe depression and reduced oral intake was admitted. She exhibited signs of dehydration and was found to have severe hypernatremia (191 mmol/L) with acute kidney injury. Treatment involved D5W, followed by D5W/half-normal saline at 150 mL/hr. Within 24 hours, her plasma sodium decreased to 178 mmol/L and gradually normalized to 143 mmol/L without neurological complications. This case highlights the challenges and underscores the importance of early recognition and management of severe hypernatremia in psychiatric patients. The primary treatment approach addresses water deficits and losses and administers D5W. Recent findings suggest that rapid correction of the condition is acceptable.